Attachment member for spring or spring-like element

ABSTRACT

A foot member is disclosed for use in attaching a spring device to a rail for cushions, seats, or foundations for a bedding product. The foot member can straddle and snap into a frame rail, or be stapled or otherwise affixed to a frame rail.

This application is a division of application Ser. No. 07/651,583, filedFeb. 6, 1991, now U.S. Pat. No. 5,332,202.

FIELD OF THE INVENTION

This invention relates generally to cushioning and support members forupholstered products, seats, bedding products, and the like, and moreparticularly to a pneumatic spring for use in such products as well asnovel attachment elements for such support members.

BACKGROUND OF THE INVENTION

In its broadest sense, the present invention addresses impact absorptionof a moving human body against a resisting surface. More specifically,and as related to the environment of bedding products to which thedescribed embodiments of the invention find illustration, the movementof a body against a cushioning and supporting surface is in point.

In general terms, an impact absorbing device should arrest a moving bodywith minimum stress of the body and the device. One may characterize theabsorption of kinetic energy in the device such that an equivalentamount may be utilized elsewhere (such as reinstating this kineticenergy back to the body at some time after impact) as an elastic impact.Alternatively an inelastic impact between the body and the device mayoccur, such that effectively all of the kinetic energy is dissipated bythe device upon impact.

Inelastic collisions may commonly be found in many safety devices suchas air bags, automobile interior panels, and crash helmets. Suchdevices, although effectively operating for their intended purpose,often may be used only once due to the severity of impact and thematerials of construction.

Between the extremes of inelastic and elastic impacts are structuresproviding elastic impacts damped by some means. Structure using suchdamping effects may rely upon the material of the structure, structuralcomponent interactions, or the environment in which the structure islocated, or some combination thereof.

In the bedding products area in which this invention finds its origin,mattress innerspring units are generally formed of a conventionalplurality of spring coils arranged in side-by-side relation in parallelrows, with parallel columns also thereby being formed orthogonal to therows. Border wires typically encircle both the upper and lowerperimeters, which for purposes of further discussion, will be referredto as top and bottom perimeters respectively. Box spring foundations arealso generally formed of a combination of helical or torsion springssupported by a base defined by wood side rails and end rails, with woodor steel spans extending between either the side or end rails. A wiregrid or the like is typically used to form the top or support surface ofthe foundation. The helical or torsional springs used in the innerspringor foundation perform the impact absorption, and then support functionsdescribed.

Besides fundamental impact absorption and support, another considerationin bedding product design and manufacture is the ability to make unitswith different firmness characteristics suited to ranges of consumerpreference. This is typically accomplished by providing several productlines having different firmness, achieved by using springs of differentspring constant or by adding/removing springs; in even moresophisticated bedding products, providing areas of differing firmness ina given bedding product by mixing spring kind or count.

As may be readily recognized, producing springs of differing springconstants, ordinarily achieved by making the various springs out ofdifferent wire stock or in different configurations, results in amultiplicity of spring manufacturing processes and the necessity ofstocking the different springs. While the overall layout, configurationor count may also be changed for each product firmness, this againincreases the number of assembly jigs required, or at a minimumincreases the complexity of product assembly.

Use of heavier wire stock, different spring fabrication machinery, moresprings, or different layouts obviously adds expense to bedding productconstruction in terms of material and labor. A significant considerationin making bedding products with different firmness characteristics istherefore to do so in the most efficient and economical manner.

Non-wire spring bedding structures have been disclosed. One example isshown in U.S. Pat. No. 3,242,512, which discloses a resilient loadsupporting device consisting of a vented bellows spring cushioningassembly. In this reference, each bellows spring component ismanufactured from a polymeric resilient and flexible material of rubberor the equivalent. Each such "spring" is formed not unlike the bellowsof an accordion, but with a circular cross-section. The thickness of thebellows varies.

Each spring of the '512 structure functions to resist a load bycollapsing along a wall circumference that is the least in thicknessuntil fully collapsed, and then a slightly thicker wall section willcollapse in a similar manner until the spring is fully collapsed.Moreover, the springs may be interleaved such that the spring ribs arein substantial contact with a neighboring spring, thereby providingadditional resistance to the collapse of an individually loaded spring.Friction between ribs of the interleaved springs during loading providesa second force counteracting the compression of a loaded spring. Thisfriction also allows for further compression of each individual rib,which reacts accordingly by expanding radially and contracting axiallythereby providing a third force grounded on the compressivecharacteristics of the material used in spring construction. Each of thehollow springs is freely vented to the atmosphere to allow the spring toreadily vent the air within the interior of the spring upon compressionas well as to refill the interior of the spring upon release of a forcefrom an impacting body. Each spring is attached to a rubber padstretched onto the base of a load supporting structure.

Similarly, in U.S. Pat. No. 3,262,138 a vented bellows assembly isdisclosed. Again, the rib bellows structures are interleaved amongthemselves and have venting sufficient to provide pneumatic resistanceto cooperate with the control cushioning effect obtained by theinteractive flexing of the bellows ribs. The springs may be secured to aload supporting structure by means of caps at either or both ends of thespring which extend through the structures.

Alternatively, an entire structure may be altered to create dampingeffects sufficient for a given use. Such structure is disclosed in U.S.Pat. No. 3,251,076. In this patent, an impact cushioning mat structureis disclosed with an interior modified to define individual air cellsinterconnected in a hexagonal or square configuration. The passage ofair between cells provides an inelastic component to the elasticbehavior of the material comprising the mat structure. In essence, theretained kinetic energy in the structure is just sufficient to restorethe mats to their original state after an impact, thereby effectivelyeliminating the possibility of a rebound of the impacting body. Thedisclosed structure resists a load by deforming a cavity in the area ofthe load which dispels air to adjoining cavities via orifices or thelike. The combination of the air pressure within the cavity and cavitystructure consequently resist the applied load and absorb the kineticenergy of the load.

Given the state of this art, it can be seen that it would be desirableto have impact absorbing and supporting devices that have non-uniformelastic propensities, such that load supporting structures composed ofindividual devices may have a gradient of "spring constants" over agiven area of the structure. It would also be desirable to have a singlespring construction that can be readily altered to change its springcharacteristics.

Moreover, there is a further need in the art for such impact absorbingdevices that provide for easy installation on bases and frames ofconventional load supporting structures in the bedding productsindustry. In this vein, it is of note that the foregoing discussion ofthe non-conventional spring references include structures of anunconventional composition that require altogether unconventional basesupports and coverings. Efforts to develop attachment elements for boththe top and bottom (i.e., the ends) of a spring which simplify assemblyof the springs into the mattress, foundation, cushion, etc., are ongoingin the bedding and furniture industries.

It is therefore an objective of this invention to provide a loadsupporting structure which utilizes pneumatic springs, is relativelysimple in construction, economical to fabricate, readily adjustable inspring characteristic, easy to assemble and install, and otherwiseideally suited to its intended purposes as a cushioning element.

SUMMARY OF THE INVENTION

The present invention comprises a pneumatic spring, as well as anassembly of such springs for use in a cushion, mattress, foundation, orthe like. In one embodiment, the pneumatic spring comprises an innersleeve and an outer sleeve which are telescoped together to form apiston cylinder. The two sleeves are joined by an elastomeric ring,which acts as a gasket and also resiliently biases the two sleeves to arest position. An air vent is provided to the piston interior.

Alternatively, in another embodiment the inner and outer sleeves areslidably engaged with each other, with a helical spring located insidethe piston formed by the sleeves, with respective ends of the springengaging respective sleeve ends. In this latter embodiment, air withinthe sleeve compartment may exit through any one or combination of: (1)an aperture or apertures in the side of a respective sleeve; (2) thearea where the sleeves engage; or (3) either end of a sleeve where asuitable valve, such as a flap valve, is advantageously located.

Either embodiment of the pneumatic spring will react as a shock absorberupon impact of a body. Both include a biasing element (elastomer or coilspring) which serves to also transform the pneumatic spring into a loadsupport element. Variability in impact absorption and support force isreadily available by easy adjustments to spring bias and venting rates.

As an incident to the development of the pneumatic spring of thisinvention, and for ease of installation to a bedding product frame, theupper terminus of the pneumatic spring has a novel attaching elementthat is dish-shaped, with integral wire clamps in a convenient geometryfor clipping onto wires of a box spring wire grid. In another relatedembodiment radially extending lobes are provided on the dish whichcooperate with radially extending flanges (or troughs) located betweenthe lobes to form a snap fit attachment element for use with a wiregrid. The spring element can simply be dropped into place within thegrid and then rotated to snap-fit the attachment element to the grid.

In addition, a respective base sleeve may be anchored to the frame of abedding product by feet having flanges which engage in slots formed in across-span, and which can alternatively be stapled to a frame span. Allof the foregoing attaching elements have application beyond those of thepneumatic spring itself.

The foregoing features and advantages of this invention will be furtherunderstood upon consideration of the following detailed description ofembodiments of the invention taken in conjunction with the accompanyingdrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view, with parts in section, of an assembly fora bedding foundation made in accordance with the teachings of theinvention;

FIG. 2 is an enlarged view depicting a single pneumatic spring of FIG.1;

FIG. 3 is a cross-sectional view of another embodiment of a pneumaticspring of the present invention;

FIG. 4 is a perspective view of the pneumatic spring of FIG. 3 betterillustrating the attachment elements at the ends of the spring;

FIGS. 5-7 illustrate different orifice arrangements for the pneumaticspring of FIGS. 3 and 4;

FIG. 8 is a plan view of a head element with integral lobes;

FIG. 9 is an elevational view of the head element of FIG. 8;

FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 8;

FIG. 11 is an enlarged cross-sectional view of an integral lobe takenalong line 11--11 of FIG. 8; and

FIG. 12 is a plan view of a head element with integral lobes afterinsertion of the spring into a wire grid, but prior to rotating forattachment to the grid.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention is hereafter described in its application in abedding product. It will nevertheless be understood that, althoughdescribed in this particular environment, the invention is considered tohave utility in other products, such as seat cushions and the likeutilizing the conventional springs that this invention is designed toreplace.

Referring now to the drawings, base 10 of a representative beddingproduct in FIG. 1--here a foundation or box spring--may be constructedin a manner similar to most bases found in a conventional foundation;i.e., with side, end and cross rails joined into a frame. A plurality ofpneumatic springs 20 are mounted on the base 10. A wire grid 30 overliesthe pneumatic springs 20 and forms the top surface to the foundation.

Each pneumatic spring 20 is anchored to the base 10 by any suitablemeans (FIG. 2), such as by stapling the widened bottom portion 14 of thespring 20 thereto. The bottom section 14 is constructed to withstand theexpected compressive forces, and to also give lateral stability to thepneumatic spring.

An inner sleeve 16 extends from the bottom portion 14. Inner sleeve 16fits within outer sleeve 18, although sleeve 16 has a much smallerdiameter. It will be noted that sleeve 16 could also be a plunger, i.e.,a solid member. The composition of sleeves 16 and 18 may be aninexpensive rigid plastic that is readily molded.

Outer sleeve 18 has a closed top end, as by widened top 28. Inner sleeve16 is closed along the bottom portion 14. An air cavity is formed by thetwo sleeves through the placement of an elastomeric ring 26circumferentially between sleeve 18 and element 16. Elastomer 26 may becomposed of any material with sufficient elasticity, such as rubber. Theelastomer ring 26 may be completely solid, or it may be discontinuousthereby providing air channels into the defined air cavity. Theelastomer ring 26 is glued along its inner and outer circumferences tothe respective sleeves.

So joined, sleeves 16 and 18 act as a pneumatic cylinder. An air vent orpassage into the air cavity in the form of a hole 29 may be providedanywhere desired in the pneumatic spring 20, as by the use of adiscontinuous elastomer ring 26 previously noted.

In normal loading of the pneumatic spring 20, sleeve 18 moves downwardlyrelative to sleeve 16, thereby compressing air in the air cavity andproducing a resistive force related to the air chamber pressure, and theelastomeric stretching force. The resistive force of the pneumaticspring 20 can be adjusted by varying one or more of: the vent hole size;the size of the air cavity; and the elastomer, for example. It will benoted that the elastomer ring 26 is of sufficient strength to return thetwo sleeves 16, 18 to a rest position when the load is removed, orsubstantially removed. The pneumatic spring 20 mimics a coil spring inthis respect.

Another embodiment of the invention is illustrated in FIGS. 3 and 4. Inthis embodiment, pneumatic spring 35 has an outer sleeve 40 slidablyengaged with an inner sleeve 42. The cross-section of the sleeves may beof any geometry, such as oval, square, rectangular, octohedron or, ashere, circular. The sleeves are made of any suitable plastic ofsufficient durability and strength for the intended purpose. As in theprevious embodiment, the sleeves 40, 42 are closed at bottom and top,respectively. Alternatively, sleeve 42 for instance may be in the formof a plunger, which would allow for elimination of open end 44.

The interior surface 41 of sleeve 40 is sufficiently smooth to allow forsmooth slidable engagement with sleeve 42. Similarly, exterior surface43 of sleeve 42 is of sufficient smoothness to allow for slidableengagement with sleeve 40. The sleeves may be sized to allow forslidable engagement of respective sleeves with an air gap or passagebetween sleeve surfaces 41 and 43 to serve as the vent previouslydiscussed in relation to the first embodiment.

Inside of the air cavity defined by sleeves 40 and 42, and extendingfrom interior bottom end 48 of sleeve 40 to interior top end 50 ofsleeve 42, is helical spring 46. This spring may be composed of anymaterial that has a durability and spring constant sufficient for theintended use. The spring 46 should be of sufficient length and reduceddiameter to allow for proper slidable movement of one sleeve withrespect to the other. Although the spring may be attached to respectiveinterior ends 48, 50 by any appropriate means, it is preferred that thespring be loose so as not to put any torque on the sleeves undercompression. It is also preferred to locate the spring inside the aircavity produced by the sleeves; locating the spring surrounding thesleeves would also be effective.

A flap valve 52 is provided at the end 50, such that the flap valve 52is hinged to open inwardly into the air cavity formed by sleeves 40 and42. Flap valve 52 covers an air vent 53.

Upon loading of the pneumatic spring 35, sleeve 42 will slide relativeto sleeve 40, thereby producing compression of the internal air cavitydefined by sleeves 40 and 42. Upon compression, flap valve 52 will seatpreventing air passage, and air will exit between sleeve 40 surface 41and sleeve 42 surface 43 in the embodiment of FIGS. 3 and 4. Spring 46also applies resistive force opposing the loading of the sleeveassembly. Compression continues until the resistive force of theassembly equals the load force applied externally to the assembly. Uponremoval of some or all of the load, spring 46 pushes sleeves 40, 42toward their rest position, with flap valve 52 opening to allow air intothe air cavity formed by the sleeves.

The compression resistance of the pneumatic spring 35 can be furthermodified through the use of various air vent shapes and combinations.For example, as shown in FIG. 5, a plurality of apertures 56 are formedin descending fashion along sleeve 42. These apertures 56 may or may notbe evenly spaced along sleeve 42. As is evident, as the sleeve 42 moveswithin sleeve 40 under load, more vent holes are covered up, yielding anincreasing rate of compression resistance. Alternatively, the vent holes56 may be formed along sleeve 40, as shown in FIG. 6. A slot 58 couldalso be provided in a sleeve, as shown in FIG. 7, to the same end.

As can therefore be seen, many useful combinations and interactionsbetween apertures and slots may be readily made to achieve the desiredcompression characteristics.

The upper end of sleeve 42 may be affixed to a conical element 70, bestshown in FIG. 4, which in the illustrated embodiment is a shallowdish-shaped right cone. The dish 70 can be integrally molded with thesleeve 42, or fixedly mounted at its frustum 72 to the end of sleeve 42by any suitable means. Dish 70 is provided with reinforcing ribs 73which criss-cross the dish.

Clips 76 are formed along the edge of the dish at 90° intervals. Theclips 76 can be deflected upwardly at their free ends 74, which areprovided with a widened hook shape. The hook shape is adapted to grasp acrosswire 32 or 34 (FIG. 3). Clips 76 cooperate with trough member 78formed integral with the dish edge. That is, a wire 32, 34 is receivedin the trough member 78, with the clip then grasping the wire. The wireis thereby clamped between clip 76 and trough 78. A reinforcing lip 80is provided around the dish edge.

In another embodiment of the attachment element of the invention, theupper end of a spring-device sleeve 108 may also be affixed to a conical(dish-shaped) element 110, shown in FIGS. 8-12, which in the illustratedembodiment is also a right circular cone. The conical element 110 can befixedly mounted at its frustum to the end of sleeve 108, or preferablyintegrally molded of the same inexpensive rigid plastic as that ofsleeve 108.

A plurality of lobes and troughs (or flanges) are formed on the coveredelement 110 to form a rotatable snap-fit attachment mechanism. Lobe 112,for instance, extends radially outward from the axis of symmetry ofconical element 110 and over long grid wire 152 and cross grid wire 156.Lobe 112 also has a pair of intersecting creases or channels formed onits underside to receive long grid wire 152 therein (FIG. 11), and/or tosimilarly receive cross grid wire 156, as well as receive their area ofwelded intersection 160.

Lobe 112 cooperates with adjacent flange or trough members 114, 120,also formed integral with conical element 110 (FIG. 10). Long grid wire152 is received in a crease or channel formed in the top of troughmember 120; cross grid wire 156 is likewise received in trough member114. The tops of the trough members are roughly co-planar with theunderside of the lobe 112. The wires are thereby clamped between lobe112 and respective troughs.

Similar interactions are found between: lobe 126 and trough members 124,118 with cross grid wire 158, long grid wire 154, and weldedintersection 164; lobe 122 and trough members 124, 120 with cross gridwire 158, long grid wire 152, border wire 150, and welded intersection166; and lobe 116 and trough members 114, 118 with cross grid wire 156,long grid wire 154, and welded intersection 162. While one lobe andtrough pair might be used to hold a spring device in place, foursymmetrically spaced pairs are presently preferred (FIG. 8). This lobedhead element is obviously applicable to a wire grid defining otherrectangular openings beyond square.

Significantly, this head element may be readily installed in aconventual grid by dropping a spring with head element into a grid, asshown in FIG. 12. Lobes 112, 116, 126, 122 contact wires 152, 156, 154,158 respectively, and trough members 114, 118, 124, 120 are clear oftheir respective wires. Upon substantial contact of the lobes withrespective wires, a snap-lock fit attachment of the element to the gridis readily obtained by rotating the head element 45° (one-eighth turn)to engage the lobes over the respective wires and the trough membersunder the respective wires. The edges of the trough members and lobesreceiving the respective wires are contoured to allow rotation of thehead element in either angular direction (clockwise orcounter-clockwise) without undue resistance to a proper snap-fitattachment. The grid wires serve to pry the lobes and troughs apart topass over opposite sides of the wires, and into a position where thewires slip into respective channels, thus fixing the attachmentelements--and thereby the spring--in place on the grid.

The bottom end 48 of sleeve 40 has a foot 82, best shown in FIG. 4,formed integral therewith. The foot 82 has depending sides 83 extendingparallel to a longitudinal axis defined by the sleeves 40 and 42. Thesides 83 are spaced apart sufficiently to straddle a steel span 86.

Perpendicular to sides 83 and extending outwardly away from the axis aretabs 90, suitable for use in attaching the foot 82 to a flat surface inthe event that the foot 82 is to be mounted on top of a wood rail 100(FIG. 3), for example. A nail, staple or the like would be driventhrough the tab 90 to fix it in place.

Opposite of tabs 90 on sides 83, but in the same plane, are flanges 84extending inwardly toward the longitudinal axis previously defined.Flanges 84 are designed to be inserted into slots 89 in the steel span86. The foot can thus be simply mounted in a clip-on fashion. The bottom48 of sleeve 40 (i.e., the top of the foot 82) preferably rests on thetop of the span 86. As can be seen, foot 82 has universal application toa wood side rail 100 or to span 86, thereby promoting the utility of theassembly for any frame.

Span 86 has a neutral axis N, shown in dotted line, where bending andtorsional forces on the web are approximately equal when the span 86 isunder load. The slots 89 are formed along the neutral axis in sufficientfrequency and position to allow for optimizing various applications ofthe pneumatic spring 35, while maintaining the structural integrity ofspan 86.

Thus, while the invention has been described with reference toparticular embodiments, modifications of structure, materials and thelike will be apparent to those skilled in the art, yet still fall withinthe scope of the invention.

What is claimed is:
 1. A mount for a spring-device used in bedding andcushions, comprising:a foot member formed on an end of a spring-devicemember for attachment to a frame, said foot member comprising a basefrom which depend a pair of opposed sides, said sides each having aflange extending inboard toward one another, said flanges being adaptedto be received in slots formed in a rail which is part of said frame,with said foot base resting on the rail when said flanges are soreceived in the slots, and an ear formed on each of said depending sidesand extending outboard, said ears being adapted to receive a staple orother attachment means to fix said ear to a frame rail as an alternativeto use of said flanges.
 2. A mount for a spring-device used in beddingand cushions, comprising:a foot member for attachment to a frame, saidfoot member comprising a base from which depend a pair of opposed sides,at least one of said depending sides having a flange extending inboard,said flange being adapted to be received in one of a plurality of slotsformed in a rail which is part of said frame, with said foot member baseresting on the rail when said flange is so received in the slot, and anear formed on at least one of said depending sides and extendingoutboard, said ear being adapted to receive a staple or other attachmentmeans to fix said ear to a frame rail.